| 摘要 |
PURPOSE:To obtain a stable picture for the video output even in case such fault occurs that has a luminance level getting into a video signal input from the pedestal toward the negative direction, by installing a pulse detecting circuit incorporating an H gate. CONSTITUTION:An AND circuit 50 receives the output of a differentiator 48 to which a composite synchronous signal separated from a composite color TV signal is supplied. A horizontal synchronous pulse separator 18 is connected to the output of the circuit 50. A pulse sensor is connected to the separator 18. A decoder 60 is connected to the output of a counter 58 to which the subcarrier separated from a TV signal is supplied. The counter 58 is loaded by at least either the output of a pulse sensor or the output of the decoder 60. At the same time, the output of the decoder 60 is exchanged with a high-level signal to be supplied to the circuit 50. |
